table join speed

I'm having a problem, where a map service I publish with a graphics table joined to a non-graphics table displays VERY SLOWLY! I'm running ArcGIS Server 10.3.1, and the other services I publish without tables joined appear to perform fine.

I tried indexing the join fields on both sides of the join, and this helped a bit, but the service remains VERY SLOW, meaning it takes 15-20 seconds for about 60 resulting graphics to display on my map.